Windows Server 2012 r2 BSOD, PowerPath Driver (EmcpMpx.sys) Implicated


Microsoft Windows Server 2012 R2 encounters a Blue Screen of Death and points to the Dell EMC PowerPath driver EMCPMPX.SYS as the cause.


This is known to affect users running

  • PowerPath for Windows 5.X SPX
  • PowerPath for Windows 6.0 SPX



10/27/2016 11:23:51 AM Error {ServerName} 1001 Microsoft-Windows-WER-SystemErro The computer has rebooted from a bugcheck. The bugcheck was: 0x000000d1 (0xffffe00171400000, 0x0000000000000002, 0x0000000000000000, 0xfffff801b86f3dd9). A dump was saved in: C:\Windows\{memory}.dmp. Report Id: {report-id}.

WinDbg Dump Output Examples:


BugCheck D1, {ffffe8015cc0f000, 2, 0, fffff800a7f4ee81}

*** ERROR: Symbol file could not be found. Defaulted to export symbols for EmcpMpx.sys -
*** ERROR: Symbol file could not be found. Defaulted to export symbols for MPIO.SYS -
Probably caused by : EmcpMpx.sys ( EmcpMpx!EmcpMpxLogPlatfEvent+3f99 )




BugCheck D1, {ffffe00171400000, 2, 0, fffff801b86f3dd9}


*** WARNING: Unable to verify timestamp for EmcpMpx.sys

*** ERROR: Module load completed but symbols could not be loaded for EmcpMpx.sys

Probably caused by : EmcpMpx.sys ( EmcpMpx+8dd9 )




Beginning with Microsoft hotfix KB3185297, they addressed an issue that occurs with any MPIO attached SAN disk when multiple paths failover concurrently, or in quick succession which causes the I/O operation to fail. This could cause the computer to lose its connection to the storage device.


During the November 2016 rollup KB3197875, they have included all previous updated (KB3185297, KB3185331, and KB3192404)



As prescribed by Dell EMC KB490865, if any of the above hotfixes are installed, remove them and reboot the machine. Dell EMC Engineering has reproduced this issue in the lab and are currently working with Microsoft to resolve the problem.


For the time being, please refrain from installing Microsoft KBs: KB3185279, KB3185331, KB3192404 and KB3197875.